Saying X would make a good candidate except for Y is the issue of course, Y exists and is known.
That a candidate is a veteran is fine with me, Rueben Gallego (D) Senator elect in AZ, served with my son's unit, and wrote a book about it. So, he's not only a veteran but also a Marine with combat experience and a CAR. Mayne that made a difference. He's pretty liberal, but not crazy progressive.
I lean to thinking combat vets understand a bit about how war is a really really bad thing and MIGHT not get us into conflicts as readily as others.
Of course, JFK was a combat vet and got on the road to the Vietnam conflict and Bush 2 got us into Iraq and Afg, but he never saw combat of course. Carter was in the Navy.